When cutting precious stones the stones must be perfectly centered on an associated dop stick in order to retain maximum weight of the stone and in order to have straight, unflared facets on the stone after cutting. Although various forms of workpiece centering fixtures heretofore have been provided, most of these have not been specifically designed for use in centering a gem stone on a dop stick and those which have been adapted for such purpose have not been readily adjustable to accommodate different size stones as well as different size dop sticks. Accordingly, a need exists for a gem stone centering tool which may be utilized to center gem stones of different sizes on dop stocks of different sizes.
Examples of previously known forms of centering fixtures, including some of the general structural and operational features of the instant invention, are disclosed in U.S. Pat. Nos. 2,416,703, 2,549,332, 2,970,495 and 3,327,399.